1. Field of the Invention
This invention relates to a disc cartridge having rotatably housed therein a disc, having information signals recorded thereon, such as a magnetic disc or an optical disc. More particularly, it relates to a disc cartridge having a main cartridge body member having discrimination holes for specifying the design parameters of a disc accommodated therein, such as a recording capacity.
2. Description of the Related Art
Heretofore, a disc cartridge 90, having housed therein an information-recording disc, such as a magnetic disc or an optical disc, has a main cartridge body member which is comprised of an upper cartridge half 91 and a lower cartridge half 92 combined together. Within this main cartridge body member 98 is rotatably housed a disc. In the upper and lower surface of the main cartridge body member 98 are formed recording/reproducing apertures, not shown, for facing each other. On the main cartridge body member 98 is movably mounted a shutter member 93 for opening/closing the recording/reproducing apertures, as shown in FIGS. 1 and 2.
Centrally of the lower cartridge half 92 of the main cartridge body member 98 is formed an opening 94 for entrance of a turntable provided on a recording and/or reproducing apparatus, not shown. This opening 94 for table entrance permits a center hub 95 mounted centrally of the disc housed within the main cartridge body member 98 to be exposed to outside the main cartridge body member 98.
The main cartridge body member 98 includes a mistaken erasure inhibiting member 96 for preventing erasure of previously recorded information signals caused by mistaken overwriting of new information signals on the disc housed within the main cartridge body member 98. This mistaken erasure inhibiting member 96 opens or closes a mistaken recording discriminating hole 97 formed in the main cartridge body member 98 for switching between the state of enabling the recording of the information signals and the state of disabling the recording of the information signals on the disc. The main cartridge body member 98 also has recording capacity discriminating holes 99A, 99B for discriminating the recording capacity of the disc housed therein.
The information signals handled by the information processing apparatus have become diversified, such picture or speech data as well as text data are handled by the information processing apparatus, and the information volume handled at a time is also increasing. For efficient transmission or recording of the large-capacity information, it is necessary to increase the recording capacity of the disc cartridge 90 used as a recording medium for information signals.
Thus, such a disc cartridge is proposed in which a disc contained in the main body member has a different recording capacity despite substantially common outer size or design parameters of the disc cartridge. Thus it becomes necessary to provide suitable discrimination means for discriminating the recording capacity of the disc housed within the disc cartridge for discriminating whether or not the disc can be used on the recording/reproducing apparatus.
As a disc cartridge having means for discriminating the recording capacity of the disc housed therein, one configured as shown in FIG. 3 is proposed. Such disc cartridge 101, shown in FIG. 3, has housed therein a disc having a recording capacity of not more than 1 megabytes (MB), and is designed to indicate the recording capacity by capacity display 101a, 101b formed by printing or impression on a shutter member 93 mounted for movement on the main cartridge body member 98 or on the main cartridge body member 98.
Another disc cartridge 102, shown in FIG. 4, has housed therein a disc having a storage capacity of 2 MB. For distinction from other disc cartridges housing therein discs having different recording capacities of not more than 2 MB, this disc cartridge 102 has, in its lower half 102A, a recording capacity discrimination hole 110 in a lateral side thereof facing the lateral side provided with the mistaken erasure inhibiting member 96. The disc cartridge 102, having housed therein the disc having the recording capacity of 2 MB, has its recording capacity detected by the recording and/or reproducing apparatus detecting the recording capacity discrimination hole 110 on loading the disc cartridge 102 on the recording and/or reproducing apparatus.
A disc cartridge 103, shown in FIG. 5, has housed therein a disc having a recording capacity of 4 MB. For distinction from the disc cartridge 102 housing therein a disc having the recording capacity of 2 MB, the disc cartridge 103 has, in its lower half 103A, a recording capacity discrimination hole 111 offset from the recording capacity discrimination hole 110 provided in the disc cartridge 102 for 2 MB disc.
A disc cartridge 104, shown in FIG. 6, has housed therein a disc having a recording capacity of 13 MB, while a disc cartridge 105, shown in FIG. 7, has housed therein a disc having a recording capacity of 21 MB. For distinction from the disc cartridges 101, 102 and 103 housing therein discs having different recording capacities, the disc cartridges 104, 105 have lower cartridge halves 104A, 105A thereof making up the main cartridge body members 98 formed with mistaken erasure inhibiting members 106 and recording capacity discriminating holes 112. These mistaken erasure inhibiting members 106 and recording capacity discriminating holes 112 are formed at reversed relative positions with respect to the mistaken erasure inhibiting members 97 and recording capacity discriminating holes 110 of the disc cartridges 101 to 103 for discs having different recording capacities. The mistaken erasure inhibiting members 106 are arranged for movement within openings 107 formed in the lower cartridge halves 98 for opening or closing the openings 107 formed in the lower halves 104A, 105A.
The recording capacity discrimination hole 112, formed in each of the disc cartridge 104 for 13 MB disc and the disc cartridge 105 for 21 MB disc, is set to represent a state judged in the disc cartridge for a disc with 4 MB or less to be a writing inhibition state. That is, since the disc cartridge 104 or 105 is set to the writing inhibiting state, when loaded on the recording and/or reproducing apparatus for discs having a recording capacity of 4 MB or less, there is no risk of inadvertent erasure of the information signals as a result of writing of the information signals.
In the conventional disc cartridges 102 to 105, the recording capacity discrimination holes 110, 111 and 112 and the second recording capacity discrimination holes 113, 114 are formed on various sites on the major surfaces of the lower halves 102A to 105A making up the main cartridge body members.
Thus, for discriminating the recording capacity of the conventional disc cartridges 101 to 105, it is necessary for the user to visually check the capacity indications formed such as by printing on the shutter member 93 or on the main cartridge body member 98 to render it difficult to quickly check the recording capacity.
Moreover, the conventional disc cartridges 101 to 105 present a problem in that the user desiring to discriminate the recording capacity has no alternative but to visually check the recording capacity indications.
In addition, it is required of the disc cartridge to increase the recording capacity such that a disc cartridge having a recording capacity of 21 MB or more needs to be clearly distinguished from the above-mentioned conventional disc cartridges 101 to 105.